2002-11-03 Roland McGrath <roland@redhat.com>

	* sysdeps/generic/ldsodefs.h (struct rtld_global): New member
	`_dl_tls_static_used'.
	* sysdeps/generic/libc-tls.c (_dl_tls_static_used): New variable.
	(__libc_setup_tls): Initialize it.  Let the initial value of
	_dl_tls_static_size indicate some surplus space in the computed value.
	* elf/dl-open.c (_dl_tls_static_size): New variable.
	* sysdeps/generic/dl-tls.c (_dl_determine_tlsoffset): Initialize
	_dl_tls_static_used.  Add some surplus space into _dl_tls_static_size.
	* elf/dl-reloc.c [USE_TLS] (allocate_static_tls): New function.
	(CHECK_STATIC_TLS): Use it.
	* elf/dl-close.c (_dl_close): Adjust _dl_tls_static_used when the
	closed objects occupied a trailing contiguous chunk of static TLS area.

2 files changed, 44 insertions, 1 deletions

diff --git a/elf/dl-open.c b/elf/dl-open.c
index 0e74996..7dd18b7 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -34,6 +34,12 @@
 #include <dl-dst.h>
 
 
+#ifdef SHARED
+/* Giving this initialized value preallocates some surplus bytes in the
+   static TLS area, see __libc_setup_tls (libc-tls.c).  */
+size_t _dl_tls_static_size = 576;
+#endif
+
 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
 				    void (*dl_main) (const ElfW(Phdr) *phdr,
 						     ElfW(Word) phnum,
diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
index 16017b3..37c4be2 100644
--- a/elf/dl-reloc.c
+++ b/elf/dl-reloc.c
@@ -35,6 +35,33 @@
 #endif
 
 
+#ifdef USE_TLS
+/* We are trying to perform a static TLS relocation in MAP, but it was
+   dynamically loaded.  This can only work if there is enough surplus in
+   the static TLS area already allocated for each running thread.  If this
+   object's TLS segment is too big to fit, we return false.  If it fits,
+   we set MAP->l_tls_offset and return true.  */
+static bool
+allocate_static_tls (struct link_map *map)
+{
+  size_t offset = roundup (GL(dl_tls_static_used), map->l_tls_align);
+  if (offset + map->l_tls_blocksize > (GL(dl_tls_static_size)
+# if TLS_TCB_AT_TP
+				       - TLS_TCB_SIZE
+# elif TLS_DTV_AT_TP
+  /* dl_tls_static_used includes the TCB at the beginning.  */
+# else
+#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+# endif
+				       ))
+    return false;
+  map->l_tls_offset = offset;
+  GL(dl_tls_static_used) = offset + map->l_tls_blocksize;
+  return true;
+}
+#endif
+
+
 void
 _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
 		     int lazy, int consider_profiling)
@@ -159,9 +186,19 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
 	     l->l_lookup_cache.value = _lr; }))				      \
      : l->l_addr)
 
+    /* This macro is used as a callback from elf_machine_rel{a,} when a
+       static TLS reloc is about to be performed.  Since (in dl-load.c) we
+       permit dynamic loading of objects that might use such relocs, we
+       have to check whether each use is actually doable.  If the object
+       whose TLS segment the reference resolves to was allocated space in
+       the static TLS block at startup, then it's ok.  Otherwise, we make
+       an attempt to allocate it in surplus space on the fly.  If that
+       can't be done, we fall back to the error that DF_STATIC_TLS is
+       intended to produce.  */
 #define CHECK_STATIC_TLS(map, sym_map)					      \
     do {								      \
-      if (__builtin_expect ((sym_map)->l_tls_offset == 0, 0))		      \
+      if (__builtin_expect ((sym_map)->l_tls_offset == 0, 0)		      \
+	  && !allocate_static_tls (sym_map))				      \
 	{								      \
 	  errstring = N_("shared object cannot be dlopen()ed");		      \
 	  INTUSE(_dl_signal_error) (0, (map)->l_name, NULL, errstring);	      \